The present invention relates to a CAE (Computer Aided Engineering) for automating and optimizing design works, through numerical analytic simulation with using a computer, and in particular, it relates to a technology for generating mesh data for use in analyzing (i.e., mesh for numerical simulation) from configuration data, which is obtained about a target to be analyzed or simulated (i.e., an analysis or simulation target), through a three-dimensional configuration measuring apparatus.
In a field of the CAE, there is already known a technology of conducting an analytic simulation, through obtaining the configuration data relating to the configuration surface of the analysis target, thereby generating the mesh for numerical simulation from that configuration data. This technology is high in availability, in particular, from a viewpoint that it enables an analytic simulation about an actual target as it is. Upon such analyzing, it is common that the configuration mesh data is generated in the form of triangle mesh data, from the configuration data of the analysis target, which can be obtained through measurement by means of the three-dimensional configuration measuring apparatus, and that from that configuration data is generated the mesh for numerical simulation in the form of a tetrahedral mesh data.
As a method for generating the tetrahedral mesh data within an inside of the configuration of the analysis target, in the form of the mesh for numerical simulation thereof, from the triangle mesh data, being the configuration mesh data for presenting configuration surface of the analysis target, there are already known the Deloni's dividing method and the Yagi's dividing method, etc. In the Deloni dividing method, first of all rough tetrahedral mesh data is generated from the triangle mesh data of the configuration surface, and then the rough tetrahedral mesh data is fragmentized through sequentially adding points within an inside of the configuration; thereby generating the tetrahedral mesh data of high quality for use in the numerical simulation thereof (see for example the following Patent Documents 1 and 2). On the other hand, the Yagi's dividing method is a method of obtaining the mesh data within an inside of the configuration, though cutting orthogonal gratings (i.e., hexahedron gratings) by the triangle mesh of the configuration surface, while setting up the orthogonal gratings to include the triangle mesh data of the configuration surface therein; i.e., in particular, the tetrahedron within an inside of the configuration is divided into a plural number of tetrahedrons, so as to generate the tetrahedral mesh data (see for example the following Patent Document 3).
Also, when generating the mesh for numerical simulation from the configuration data, there are many cases where it is necessary to generate one (1) piece of the mesh for numerical simulation, with using a plural number of pieces of configuration mesh data. Thus, in cases where the analysis target is large in the sizes and/or complex in the structures thereof, or in case when trying to obtain the configuration data at much higher accuracy thereof, it is necessary to pick up pictures of the analysis target, while dividing it into plural numbers of areas thereof, when obtaining the configuration data at the accuracy that is needed by picking up an image of the analysis target through an X-ray CT apparatus, for example. In such cases, plural pieces of configuration mesh data are obtained for one (1) piece of the analysis target, and there is necessity of a process for combining or unifying each of respective configuration mesh data, so as to generate one (1) piece of the mesh for numerical simulation (i.e., analysis use mesh data) from those plural pieces of the configuration mesh data.
For generating one (1) piece of the mesh data through combining or unifying the plural pieces of the mesh data, there is already known a method of moving the joints at connection portions of the mesh data, thereby to connect them, or a method of dividing a ridgeline on the mesh data to be connected so that the joint positions can be commonly shared with each other, thereby to connect them (for example, in the following Patent Document 4). Further, there is also known a method of designating the relative positions of the mesh data, thereby to connect the mesh data with each other (for example, in the following Patent Document 5).
Patent Document 1: Japanese Patent Laying-Open No. Hei 11-110587 (1999);
Patent Document 2: Japanese Patent Laying-Open No. Hei 11-96399 (1999);
Patent Document 3: Japanese Patent Laying-Open No. 2005-38219 (2005);
Patent Document 4: Japanese Patent Laying-Open No. 2002-318823 (2002); and
Patent Document 5: Japanese Patent Laying-Open No. 2000-331058 (2000).
The three-dimensional configuration measuring apparatus of recent years, in particular, the X-ray CT apparatus is able to obtain the configuration data at high configuration accuracy thereof, and it makes an advance into high density of the configuration mesh data and an increase of the data volume thereof. Accompanying with such an increase of the data volume, it results into problems in processing capacity of the computer; i.e., that it takes an extensive amount of times in the process for generating the mesh for numerical simulation from the configuration mesh data, as well as, in the process for analyzing the mesh for numerical simulation thereof, and further that those processes go beyond the limit of capacity of the computer. And, such the problems of processing capacity comes to be further serious, in particular, when there are plural configuration mesh data for one (1) piece of the analysis target, and those are necessary to be processed in combination, as was mentioned above. Namely, if applying the conventional combining method, such as, of dividing the ridgeline and thereby combining the meshes divided, for example, into the combining processes, then the number of the meshes is further increased, and therefore, there may be a high possibility that the increasing data volume exceeds the limit of data volume, which the computer can deal with, and then the computer cannot process the combination of the configuration data.
About the problem of such processing capacity, it is possible to deal with, by reducing the number of meshes of the configuration data; i.e., a process of lowering the density thereof. However, with such the process of simply reducing the number of meshes; i.e., lowering the density thereof, on the contrary, but there is caused other problem, such as, that the configuration errors are increased on the mesh for numerical simulation, although applying the configuration data at high accuracy with much trouble therein, for example. Further, it is also possible to deal with such the problems of processing capacity, through a method of reducing the number of addition of the interior points within the Deloni's dividing method, or of enlarging the distance of the orthogonal grating in the Yagi's dividing method; however, in the similar manner, those methods also cause the problems, such as, the configuration errors on the mesh for numerical simulation and lowering the quality of the mesh for numerical simulation.